Ezra Shaw/Getty Images(SAN FRANCISCO) -- A teenager who was thrown to the runway in the Asiana Airways plane crash earlier this month was killed when she was run over by at least one and maybe two rescue vehicles racing to the crash, officials said on Friday.

The cause of death for Ye Mengyuan, 16, was multiple blunt trauma "consistent with being run over by a motor vehicle," San Mateo County Coroner Robert Foucrault said in a news conference Friday. A forensic examination revealed that she was alive at the time when she was hit, he said.

San Francisco Fire Chief Joanne Hayes-White said she believes it was a specialized rig that came from the airport that fatally struck Mengyuan.

"My understanding is that she was not standing up. She was on the ground when our rigs, one rig or possibly two, made contact with her," Hayes-White said.

Asiana Airlines Flight 214, which originated in Shanghai and had a stopover in Seoul, South Korea, was carrying 291 passengers and 16 crew members when it crashed on the runway at San Francisco International Airport and burst into flames on July 6.

Mengyuan and Wang Linjia, both 16 and students from China, had been sitting in the rear of the plane and were tossed out of the plane when the tail smashed into the ground and broke away from the rest of the plane. Three flight attendants were also ejected from the plane.

Mengyuan's body was found on the ground, covered in the foam sprayed to quell the flames of the Boeing 777.

Hayes-White said that emergency responders are "very emotional from this incident."

The death toll from the flight's crash rose to three on July 12 after a third young girl died from the injuries she sustained, San Francisco General Hospital said in a statement.

More than 180 people onboard were initially taken to hospitals for treatment.

Federal investigators have yet to indicate whether the crash can be attributed to pilot error, while they analyze data recovered from the plane's black boxes.

Investigators have said that Flight 214 was flying "significantly below" its target speed during approach when the crew tried to abort the landing just before the plane crashed onto the runway.